of goeggingen



June 2, 1931. E. sAcHs 1,807,637

FORM CYLINDER FOR ROTARY INTAGLIO PRINTING MACHINES Filed Jan. 18, 1927 jmmm l atented June 2, 1931 UNITED STATES PATENT OFFICE ERNST SACHS, OF GOEGGINGEN, NEAR AUGSBURG, GERMANY, ASSIGNOR OF ONE-HALF,

T9 MASCHINENFAIBRIK AUGSBURG-NUERNBERG, AK'IIENGESELLSCHAIT, OF AUGS- EBUIBG, GERMANY, AND ONE-HALF TO ASBERN MASCHINENFABRIK-AKTIENGESELL- SCHAFT, AUGS BURG-GOEGGINGEN, 0F GOEGGINGEN, NEAR AUGSBURG, GERMANY FORM CYLINDER FOR ROTARY INTAGLIO PRINTING MACHINES 7 Application filed January 18, 1927, Serial No.

My-invention relates to form cylinders for rotary intaglio printing machines and has particularly for its object, to devise an improved form cylinder of light metal for instance of aluminum and a process of making same.

- In the manufacture of such form cylinders it is very diflicult to secure the copper coating, which serves as the etching ground, immovably upon the light metal cylinder. Also in case of said copper coating is electrolytically deposited upon the light metal cylinder, it will be very difiicult to properly secure the copper coating upon the cylinder in such a manner, that said coating will firmly adhere to said cylinder during operation. J

According to the present invention, the electrolytically deposited copper coating is firmly and inseparably'connected with the light metal cylinder so that therewill be no a danger of the copper coating becoming loose during operation.

The form cylinder, according to this invention, is shown in the accompanying drawings, in which Figs. 1 and 2 are an elevation of the new cylinder, While Figs. 3 to 5 are fragmentary sections through the cylinder.

The form cylinder a, as shown in Fig. 1 is provided with a groove, or thread, bof dove-tail cross-section, as may be seen from Fig. 3. A strap, ribbon or wire 0 of'copper, or other well conducting metal, is placed into said groove, or thread, b, the cross-section of said strap, ribbon or wire 0 being shown in Fig. 4. The inner surface of the copper strap a which bears on the bottom of the groove, or thread, 6, as well as its otter surface are of arched conformation, while its lateral edges are parallel with each other, so that the copper strap 0 may easily and conveniently be placed into the groove, or thread, b. After the strap, ribbon or wire a has thus been placed into the groove, or thread, I), a strong pressure is exerted by means of a steel-roller, preferably with the aid of a lathe, upon the arched outer surface of the copper strap 0. Thereby said arched outer surface will be depressed, and

the previously parallel lateral surfaces of 161,734, and in Germany January 21, 1926.

the copper strap a will be rolled into the upon the surface of the light metal cylinder.

The metal layer, or copper coating d will thereby be firmly connected with the metal stra s c, as shown in Fig. 5.

.cof

T e grooves, or threads, I) may also be provided upon the cylindrical surface of the form cylinder a parallel with the axis of the latter. i

I claim: 1. A form cylinder for intaglio printing machines provided'with a groove opening through the cylindrical surface of the cylinder, said groove being of greater cross sectional width inwardly of the cylindrical surface of the cylinder than at said surface, a metal member disposed in said groove and conforming in cross sectional shape thereto, whereby said member is mechanically interlocked with the cylinder, and a metal coat-' ing electrolytically deposited on said cylinder and said member and electrolytically united with the latter.

2. A form cylinder for intaglio printing machines provided with a groove opening through the cylindrical surface of the cylin-,

der, said groove being of dovetail shape in cross section and of least width Where it opens through the surface of the cylinder, 21. metal strip disposed in said groove and conforming in cross sectional shape thereto,

whereby said strip is mechanically inter the latter.

3. The method of providing an etching surface on a form cylinder for intaglio printing machines which consists in forming in the cylinder a groove opening through the cylindrical surface of the cylinder, forming an inner portion of said groove of greater width -than an outer portion thereof,

placing a metal filler element in said groove, applying inward pressure against said filler element to expand the same into the portion of the groove of greatest width, thereby to mechanically interlock the filler element with the cylinder, and electrolytically depositing a coating of etching metal on said cylinder and said filler element.

4:. The method of providing an etching surface on a form cylinder for intaglio printing machines which consists in forming in the cylinder a groove .opening through the cylindrical surface of the cylinder, forming an inner portion of said groove of greater width than an outer portion thereof, providing a filler element for said groove having a cross section equal to the cross section of the groove and normally of a greatest width less than the least width of the groove, placing said filler element in the groove, applying inward pressure against said filler element to expand the same into the groove until the outer surface of the filler element forms in efi'ect a flush continuation of the cylindrical surface of the cylinder, and electrolytically depositing a coating of etching metal on said cylinder and said filler element.

5. The method of providing an etching surface on a form cylinder for intaglio printing machines which consists in forming in the cylinder a roove opening through the cylindrical sur ace of the cylinder, laying a filler element of electrical conducting metal in said groove, applying inward pressure against said filler element to expand the same into firm engagement with the walls defining the groove, and electrolytically depositing a coating of etching metal on said cylinder and said filler element.

In testimony whereof I have affixed my signature.

ERNST SACHS. 

